I can form you can form he can form we can form you can form they can form
V-ing form
I can be forming you can be forming he can be forming we can be forming you can be forming they can be forming
Perfect
I can have formed you can have formed he can have formed we can have formed you can have formed they can have formed
V-ing perfect
I can have been forming you can have been forming he can have been forming we can have been forming you can have been forming they can have been forming
Negation
Simple form
I cannot form you cannot form he cannot form we cannot form you cannot form they cannot form
V-ing form
I cannot be forming you cannot be forming he cannot be forming we cannot be forming you cannot be forming they cannot be forming
Perfect
I cannot have formed you cannot have formed he cannot have formed we cannot have formed you cannot have formed they cannot have formed
V-ing perfect
I cannot have been forming you cannot have been forming he cannot have been forming we cannot have been forming you cannot have been forming they cannot have been forming
Interrogative form
Simple form
can I form? can you form? can he form? can we form? can you form? can they form?
V-ing form
can I be forming? can you be forming? can he be forming? can we be forming? can you be forming? can they be forming?
Perfect
can I have formed? can you have formed? can he have formed? can we have formed? can you have formed? can they have formed?
V-ing perfect
can I have been forming? can you have been forming? can he have been forming? can we have been forming? can you have been forming? can they have been forming?
Interro-negative form
Simple form
can I not form? can you not form? can he not form? can we not form? can you not form? can they not form?
V-ing form
can I not be forming? can you not be forming? can he not be forming? can we not be forming? can you not be forming? can they not be forming?
Perfect
can I not have formed? can you not have formed? can he not have formed? can we not have formed? can you not have formed? can they not have formed?
V-ing perfect
can I not have been forming? can you not have been forming? can he not have been forming? can we not have been forming? can you not have been forming? can they not have been forming?